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mag_pbg
02-08-2004, 06:36 PM
I did a search and I couldn't find anything over the subject. my question is will it make a HP gain and how would I do it.

1988starter
02-08-2004, 07:08 PM
compression raising is one of the best gains in my oppinion. There are 3 common ways to do it mill the head the block or get high compresstion pistons

k-roy
02-08-2004, 07:27 PM
You can always get a A18 head off a Prelude to raise the sompression.

mag_pbg
02-08-2004, 07:30 PM
Sounds good, but which is the cheapest, maybe the A18 head swap¿ What model does that come off of¿

shepherd79
02-08-2004, 08:01 PM
the problem with A18 head is that A20 EFI manifold won't bolt up. A18 head has diff bolt pattern. it is good upgrade if you are going with dual sidedraft weber carb setup.
the easiest way would be is to replace the pistons.

johnwc723
02-08-2004, 08:16 PM
how do head grinds work anways? is that a really complicated thing to do?

Volitech
02-08-2004, 10:19 PM
how do head grinds work anways? is that a really complicated thing to do?

It's not complicated at all it's fairly simple and relitively cheap compared with a total rebuild! It just requires a little down time and a mill. Midwest engine exchange in madison will do it for about $100 wich includes hot tanking and magnafluxing it! I'm droping mine off this week too be done! :)

SteveDX89
02-09-2004, 03:09 AM
You could use a thinner head gasket but that won't give you a whole lot of difference. Not even sure if they make them for the 3g but that's another way to do it.

Cyric_accord
02-09-2004, 09:13 AM
It's not complicated at all it's fairly simple and relitively cheap compared with a total rebuild! It just requires a little down time and a mill. Midwest engine exchange in madison will do it for about $100 wich includes hot tanking and magnafluxing it! I'm droping mine off this week too be done! :)

The only thing is the timing becomes slightly screwed up when you mill the head since the clearance has changed.... good thing to get an adjustable cam gear.


And where is Midwest Engine? I'm from the village of Oregon, and I drive thru madison pretty often, but I haven't seen it.

BootMachine
02-09-2004, 11:30 AM
I have two A18 heads with less than 180 000 KMS on them. One of them is ported and polished! They are both from sidedraft preludes!

NXRacer
02-09-2004, 12:28 PM
check out www.accordcentral.com they have head packages, and high comp pistons.

hondamanlxi
02-09-2004, 01:20 PM
could you run just high-comp pistons? would you still be able to run nitro?

johnwc723
02-09-2004, 01:29 PM
alright volitech you will have to tell me how all this stuff works out, im thinking of doin it as long as it works for you :) damn we need a madison meet hardcore there are alot of us (4 at least now!) that live near madison

Cyric_accord
02-09-2004, 01:52 PM
could you run just high-comp pistons? would you still be able to run nitro?

You can just get the 10.5 or 12.1 CR Diamond Pistons that sean got going and yes, you can still run nitrous, but you better be prepared to shell out for 93-octance fuel alone for the highCR pistons. Plus be ready to do some tuning so you don't lean the engine out when you run nitrous, unless you use a wet kit.

NXRacer
02-09-2004, 02:07 PM
running nitrous is a lot like running turbo so its better to run low compression if you're planning on running a large shot. If you're gonna run no larger then a 75 shot, then a high compression motor is ok, just make sure its gonna be tuned right cause you can run into a lot of problems if its not tuned right.

Volitech
02-09-2004, 03:22 PM
The only thing is the timing becomes slightly screwed up when you mill the head since the clearance has changed.... good thing to get an adjustable cam gear.


And where is Midwest Engine? I'm from the village of Oregon, and I drive thru madison pretty often, but I haven't seen it.


Midwest engine is on Millwaukee street across from woodmans! There listed in the book!

Cyric_accord
02-09-2004, 07:24 PM
Midwest engine is on Millwaukee street across from woodmans! There listed in the book!

huh, I'll have to go check them out this summer then

Justin86
02-10-2004, 12:39 PM
as for hp if you go form 8.6:1 to 9.6:1 you should gain about 10hp.

riced_roach
02-11-2004, 08:54 PM
raise the compression and increase your combustion temperatures. If your concerned with emissions be aware the your Oxides of nitrogen will go up. Pray the rodium in the catalytic converter and egr will be able to reduce NOX enough to pass gas emission tests.

skimming the head will have minimal effects on cam timing. I cannot see why people are so concerned with that issue.

I see 10:1 c/r to be a good nitrous motor. The more static compression you have the higher octane fuels and retarded timing will be required to reduce detonation. While your at it put a colder spark plug to reduce detonation.

smufguy
02-16-2004, 04:26 PM
raise the compression and increase your combustion temperatures. If your concerned with emissions be aware the your Oxides of nitrogen will go up. Pray the rodium in the catalytic converter and egr will be able to reduce NOX enough to pass gas emission tests.


You can always get a lower temp thermostat and have the radiator fan run all the time to keep the temperature much more controlled. Its not a problem for higher temperature in the combustion chamber.

Higher temperature would eliminate the NOx emissions, but your CO would not be fully burnt up due to increased temperature.

If you really think higher Compression ratio of 10-11 would be bad for emissions, get a S2000 cat and ur on the go. Cause they use 12:1 CR as you know. The only problem would be CO, if you say that the combustion chamber temp would go up, but there is always a way to fix it :D

A20A1
02-16-2004, 04:45 PM
as for hp if you go form 8.6:1 to 9.6:1 you should gain about 10hp.

I agree. I was doing computer simulations, and for every 0.1 raise in compression you'd get 1 hp. :D Though one time it took a 0.2 increase to get 1 hp.

riced_roach
02-16-2004, 06:34 PM
You can always get a lower temp thermostat and have the radiator fan run all the time to keep the temperature much more controlled. Its not a problem for higher temperature in the combustion chamber.

Higher temperature would eliminate the NOx emissions, but your CO would not be fully burnt up due to increased temperature.

If you really think higher Compression ratio of 10-11 would be bad for emissions, get a S2000 cat and ur on the go. Cause they use 12:1 CR as you know. The only problem would be CO, if you say that the combustion chamber temp would go up, but there is always a way to fix it :D

Actually higher combustion temperatures will always give you higher Nox readings guaranteed. CO has very little effect on increased temperatures since CO is a byproduct of combustion. CO readings would go up and down in relation to how much HC is burned. Hydrocarbons is raw gasoline.

Absolutely no problems with C/R since its the cheapest source of HP to get. The only bad thing about high c/r is higher combustion temperatures which will increase nox.

Adding a colder thermostat would help reduce engine temps perhaps but the problem with the fan constantly on would put the engine in "open loop" which would just make your engine operate rich more often. Plus you may get alot of condensation in the oil since it wont meet operating temperatures consitantly. Not a really good solution with a constant fan.

Justin86
02-16-2004, 07:25 PM
I agree. I was doing computer simulations, and for every 0.1 raise in compression you'd get 1 hp. :D Though one time it took a 0.2 increase to get 1 hp.
Yea I found a computer program for engine tunning..... it says it has a data base of 3,000 cars going back 20yrs so it should have are beautiful A20. http://www.3geez.com/showthread.php?t=29522

riced_roach
02-16-2004, 08:08 PM
Yea I found a computer program for engine tunning..... it says it has a data base of 3,000 cars going back 20yrs so it should have are beautiful A20. http://www.3geez.com/showthread.php?t=29522


c/r numbers as they increase are not linear to what HP you get. Every combination of will effect results. Cam, combustion chamber...etc.

desk top dynos are a general guideline but almost always off since it wont account for quality of ignition systems on high c/r engines. Too many variables.

smufguy
02-17-2004, 07:34 AM
Actually higher combustion temperatures will always give you higher Nox readings guaranteed. CO has very little effect on increased temperatures since CO is a byproduct of combustion. CO readings would go up and down in relation to how much HC is burned. Hydrocarbons is raw gasoline.

My bad, i got the thing reversed. thanks for the correction. If ur running lean then the Destruction percentage of Nox would go down. and like u said, which in other terms mean u get a lot of NOx.

But when the temperature of the combustion chamber goes down, which is ur rich, then you get a lot of CO and H0 so yeah the byproducts do depend on the Temperature of the combustion chamber which in turn depends on if ur running rich or lean or stoichometric. which is the same as u mentioned. :cool2: